Implement frame flexibility is required for proper operating depth and consistent seed placement across a wide seeding implement. A multi-section agricultural implement frame with a segmented and jointed rockshaft is often used with such implements. An actuator attached to one segment rotates the rockshaft segments to raise and lower tools connected to the frame. In many currently available seeding and tillage implements, the rockshaft is connected to lift wheel assemblies that rotate relative to the frame with movement of the actuator to change frame height. The joints connecting rockshaft segments transmit rockshaft rotation and facilitate pivoting of the frame sections when changes in terrain are encountered or when the implement frame is folded and unfolded between field-working and transport positions. Loads on the joints can be substantial, particularly when the rockshaft is part of a lift system on large tillage and seeding implements.
To adjust the operating depth of tillage or seeding tools on one frame section relative to the tools on another section, some implements have adjustable length links located between the rockshaft and the support wheels. Other adjustment structures include an adjustable turnbuckle between the mainframe and outer section rockshafts. If additional wheel assemblies are connected to the rockshaft outboard of the inner rockshaft section, individual adjustment at each outboard wheel assembly may be required to change relative operating depth. Providing convenient, consistent and precise wheel assembly adjustments is continuing source of problems with such rockshaft assemblies.